Roland Cube 60

[Buffalo Sam]

My cube 60 that I've had since the 1970's.  It seams to have developed distortion and bad sound where it shouldn't.  It used to be a VERY clean sounding amp. Now not so much.  Any suggestions on how to approach a fix for it?

[Enzo]

What is your skill level?

The key to fixing anything is to isolate the problem.

Like any other amp, it has a preamp, and a power amp, and a power supply, and of course, a speaker.

Try listening through headphones.   That will turn off the speaker.  Does it sound OK in the phones?  Or the same distortion?   And I'd still want to check the speaker, so I would disconnect the wires to the one in the amp, and run a speaker cord from the extension speaker jack to some other speaker cab for a listen.

test the power amp.  PLug your guitar or other signal into the MAIN IN jack, that is the power amp input next to the PREAMP OUT jack.   Does that come out the speaker OK or have the same problem?

You have two input jacks up front - overdrive and normal.   Are both those equally affected, or just one of them?

Run a guitar cord from the PREAMP OUT jack to the input of some other amp and speaker.  Play into the input like usual.  does the preamp sound come out the other amp OK or does it have the problem?